1. Field of the Invention
The present invention relates to a production method for a channel plate which is used to multiply charged particles such as electrons and/or ions or photons such as ultraviolet rays.
2. Description of the Prior Art
The channel plate has been used for intensifying the resolution of image which is essentially comprised of a plate member having a plurality of channels passing therethrough.
As is shown in FIG. 7 by way of example, the channel plate has such a structure that circular electrodes 5a and 5b are formed respectively on each side surface of a disk-like base plate 5 being made of a semi-conductive ceramic material having a secondary electron emission yield and a lot of micro channels 6 are formed so as to pass through said base plate parallel to each other in the direction of thickness thereof. Conventionally, there have been known, as a material for the channel plate, a semi-conductive ceramic material including barium titanate, or zinc titanate as a main component which has a high resistivity and a secondary electron emission yield, an insulative material such as a glass plate on each surface of which a thin film such as a NESA film having a high resistivity and a high secondary electron emission yield and/or a lead glass.
A variety of production methods for the channel plate have been known as follows.
According to one of production methods, nylon fibers are passed through a mass of slurry including powder of a semi-conductive ceramic material to adhere said slurry onto the surface of said fiber. These fibers are wound aligned and, then dried and burned to form channels. However, this method has disadvantages in that processes thereof are very complicated, that it is difficult to form channels in a state aligned regularly and that high skill is required in burning nylon fibers perfectly.
Also, according to the second method, thin plates of about 100 .mu.m in thickness are made by burning plates of a semi-conductive ceramic material. These plates are aligned to have an equidistance of about 100 .mu.m between adjacent plates and assembled into a block by fixing both sides thereof.
However, according to this method, it is very difficult to assemble these thin plates exactly and, also, it is difficult to fabricate the device for assembling. Further, according to this method, it is hardly possible to obtain a structure having a two dimensional arrangement of channels.
According to one method which uses glass material as a base plate, several or several tens of glass tubes are bundled and made into a block by melting to each other while pressing and heating them. The block obtained is heated up near the softening point of said glass and then, lengthened to a fine tube. After repeating these processes several times, a block is formed which has capillary-like through holes of diameter less than 100 .mu.m. Then, several blocks thus obtained are inserted into a mold integrally and melted into one piece while pressing and heating.
However, according to this method, it becomes necessary to repeat complex processes and the cost of the channel plate becomes very high due to a large number of producing steps.
In the case that lead glass is used to make a channel plate, the method thereof is essentially same to that mentioned just above, but different from the latter only in a point that lead metal is made depositted on the surface by heating said block in an ambient gas of hydrogen up to, for instance, 400.degree. C. Accordingly, this method has disadvantages similar to those of the second method mentioned above.
As is understood from the above mentioned, any of conventional method for producing channel plate has many restrictions in many points and requires high skills upon the production thereof.